Technical Field
The present invention relates to a dry cleaning apparatus having a casing having an internal space for flying cleaning members in the casing by using rotating air flow to contact or collide the cleaning members to a cleaning target for cleaning the cleaning target, a dry cleaning casing used for the dry cleaning apparatus, and an attachment method of a screen plate.
Background Art
As to soldering process by a flow solder bath used for manufacturing printed boards, a mask jig is used to mask areas not receiving the soldering process. When the mask jig such as dip pallet and carrier palette is repeatedly used for many times, flux accumulates and sticks on a surface, with which the precision of mask deteriorates. Therefore, the mask jig is required to be cleaned periodically. Typically, the mask jig is cleaned by immersing the mask jig in solvent. The cleaning process of the mask jig consumes greater amount of solvent causing increased cost, and further an operator and environment are exposed to solvent. A method of jetting solvent to a cleaning target (i.e., without immersion) in an apparatus is known, but this method also consumes greater amount of solvent.
In view of this issue, a dry cleaning apparatus has been proposed, in which a suction unit is connected to a casing having an internal space. Negative pressure is generated in the casing to inflow external air from an air flow path disposed at one portion of an outer face of the casing with high speed to generate a rotating air flow in the casing. The rotating air flow can fly and circulate thin leaf cleaning members in the casing. An opening, which has a cross-section area greater than the above mentioned air flow path, is formed on the outer face of the casing. A cleaning target is attached to the opening to cover the opening, with which the above mentioned rotating air flow is generated, and the cleaning members collide a surface of the cleaning target with high speed at the opening. By repeating this cleaning operation, contamination can be removed from the cleaning target.
A flow restriction member having cylindrical shape or column shape is disposed at the center of the casing to define a rotation axis of the rotating air flow. An outer face of the flow restriction member becomes an internal face of the rotating air flow. Substance removed from the cleaning target (hereinafter, removed substance) passes through a screen plate having a greater number of holes that do not pass through the cleaning members, and recovered to a suction unit. The screen plate is a punched metal plate, and is disposed at a side of the suction unit in the casing, which is at a connection part of the casing and the suction unit as a face parallel to a movement direction of the rotating air flow. The screen plate is set perpendicular to the flow restriction member.
When the cleaning target is detached or removed from the opening, a greater amount of air inflows in the casing from the opening, and an air-inflow amount from the air flow path suddenly decreases, with which the rotating air flow disappears, and the cleaning members are adsorbed on the screen plate and retained in the casing. When a cleaning target is attached to the opening to cover the opening again under this condition, the rotating air flow is generated again to fly the cleaning members adsorbed on the screen plate. For example, JP-2012-050973-A and JP-2012-121017-A disclose a configuration having a flow restriction member as a porous member, in which the flow restriction member itself can function as a screen plate.